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    <div class="refentry" id="glStencilMaskSeparate">
      <div class="titlepage"/>
      <div class="refnamediv">
        <h2>Name</h2>
        <p>glStencilMaskSeparate — control the front and/or back writing of individual bits in the stencil planes</p>
      </div>
      <div class="refsynopsisdiv">
        <h2>C Specification</h2>
        <div class="funcsynopsis">
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glStencilMaskSeparate</strong>(</code>
              </td>
              <td>GLenum <var class="pdparam">face</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLuint <var class="pdparam">mask</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
        </div>
      </div>
      <div class="refsect1" id="parameters">
        <h2>Parameters</h2>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>face</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    Specifies whether the front and/or back stencil writemask is updated.
                    Three symbolic constants are valid:
                    <code class="constant">GL_FRONT</code>,
                    <code class="constant">GL_BACK</code>, and
                    <code class="constant">GL_FRONT_AND_BACK</code>.
                </p>
            </dd>
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>mask</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    Specifies a bit mask to enable and disable writing of individual bits
                    in the stencil planes.
                    Initially, the mask is all 1's.
                </p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1" id="description">
        <h2>Description</h2>
        <p>
            <code class="function">glStencilMaskSeparate</code> controls the writing of individual bits in the stencil planes.
            The least significant
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math>
            bits of <em class="parameter"><code>mask</code></em>,
            where
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math>
            is the number of bits in the stencil buffer,
            specify a mask.
            Where a 1 appears in the mask,
            it's possible to write to the corresponding bit in the stencil buffer.
            Where a 0 appears,
            the corresponding bit is write-protected.
            Initially, all bits are enabled for writing.
        </p>
        <p>
            There can be two separate <em class="parameter"><code>mask</code></em> writemasks; one affects back-facing polygons, and the other
            affects front-facing polygons as well as other non-polygon primitives.
            <a class="citerefentry" href="glStencilMask.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilMask</span></span></a> sets both front
            and back stencil writemasks to the same values, as if
            <a class="citerefentry" href="glStencilMaskSeparate.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilMaskSeparate</span></span></a> were called
            with <em class="parameter"><code>face</code></em> set to <code class="constant">GL_FRONT_AND_BACK</code>.
        </p>
      </div>
      <div class="refsect1" id="errors">
        <h2>Errors</h2>
        <p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>face</code></em> is not one of the accepted tokens.
        </p>
      </div>
      <div class="refsect1" id="associatedgets">
        <h2>Associated Gets</h2>
        <p>
            <a class="citerefentry" href="glGet.xhtml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
            <code class="constant">GL_STENCIL_WRITEMASK</code>, <code class="constant">GL_STENCIL_BACK_WRITEMASK</code>,
            or <code class="constant">GL_STENCIL_BITS</code>
        </p>
      </div>
      <div class="refsect1" id="versions">
        <h2>API Version Support</h2>
        <div class="informaltable">
          <table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">
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              <col style="text-align: center; " class="firstvers"/>
              <col style="text-align: center; " class="lastvers"/>
            </colgroup>
            <thead>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; ">
                 
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; " colspan="2">
                <span class="bold"><strong>OpenGL ES API Version</strong></span>
            </th>
              </tr>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>Function Name</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>2.0</strong></span>
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.0</strong></span>
            </th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; ">glStencilMaskSeparate</td>
                <td style="text-align: center; border-right: 2px solid ; ">✔</td>
                <td style="text-align: center; ">✔</td>
              </tr>
            </tbody>
          </table>
        </div>
      </div>
      <div class="refsect1" id="seealso">
        <h2>See Also</h2>
        <p>
            <a class="citerefentry" href="glColorMask.xhtml"><span class="citerefentry"><span class="refentrytitle">glColorMask</span></span></a>,
            <a class="citerefentry" href="glDepthMask.xhtml"><span class="citerefentry"><span class="refentrytitle">glDepthMask</span></span></a>,
            <a class="citerefentry" href="glStencilFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a>,
            <a class="citerefentry" href="glStencilFuncSeparate.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilFuncSeparate</span></span></a>,
            <a class="citerefentry" href="glStencilMask.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilMask</span></span></a>,
            <a class="citerefentry" href="glStencilOp.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>,
            <a class="citerefentry" href="glStencilOpSeparate.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilOpSeparate</span></span></a>
        </p>
      </div>
      <div class="refsect1" id="Copyright">
        <h2>Copyright</h2>
        <p>
            Copyright <span class="trademark"/>© 1991-2006 Silicon Graphics, Inc.
            Copyright <span class="trademark"/>© 2010-2014 Khronos Group.
            This document is licensed under the SGI Free Software B License.
            For details, see
            <a class="link" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p>
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